Mining and mineral resources of Minnesota

Q: What kinds of mining occur in Minnesota and where?

A: Minerals of economic significance found in Minnesota can be divided into two broad classes: metallic minerals, and industrial minerals. Metallic minerals are further divided into ferrous minerals, which contain mainly iron, and nonferrous minerals, which do not contain iron but have other metals such as copper.

Metallic minerals

Minnesota is by far the largest producer of the ferrous minerals iron ore and taconite in the United States. Even though nearly all of the high grade iron ore in Minnesota has already been mined, advances in technology have made possible the use of low-grade iron ore, called taconite. Taconite mining occurs on the Mesabi iron range in northeastern Minnesota. Furthermore, iron ore is being recovered from old iron mining waste materials, called tailings, on the Mesabi Range.

Non-ferrous minerals manganese, copper, nickel, platinum, and titanium exist in Minnesota in minable quantities, but under current market conditions are not being mined. Quantities and precise locations of gold, diamonds, zinc and lead are not well known; it remains for future exploration to reveal minable resources.

Industrial minerals

Industrial minerals include construction aggregate (sand, gravel and crushed stone), peat, kaolin clay, dimension stone, landscape stone, and silica sand.Aggregate mining operations occur in nearly every county in Minnesota. Aggregate materials are the essential elements of a variety of construction products, such as concrete. Bedrock quarries are mined to make crushed stone for construction aggregate uses. There are quarries in bedrock types such as dolomite, quartzite, granite, gabbro, and gneiss. Kaolin clay is mined in the Minnesota River Valley and is used in making cement, bricks and tiles. Silica sand, a fine sand composed of quartz, is mined in the southeastern part of Minnesota. Its uses include glass-making, a source of silicon, and in improving flow in oil wells. Dimension stone includes granite, gabbro, quartzite and carbonate rock types, which are used in the construction of homes, buildings and monuments. Peat is formed by partially decomposing plant material in wet environments, such as bogs or fens, and is used primarily as a soil amendment.

Q: What resources are available for researching the geology and mineralogy of Minnesota?

A:

Hibbing Drill Core Library: Over three million feet of mineral samples available for analysis. (One of the finest facilities of its kind in the world.) Call the Division of Lands and Minerals Hibbing Office - 218-231-8484. You can also visit the DNR's Drill Core Library webpage.

Minnesota Department of Revenue : The latest edition of the Minnesota Mining Tax Guide, which contains information on many aspects of mining production and taxes.

Q: Who regulates sand and gravel mining? What permits are required?

A: In Minnesota, gravel mining operations are generally under the jurisdiction of local government. The township, city and/or county in which the operation is located may have specific regulations for development, operation, or reclamation of a pit. Additionally, a number of state and federal permits may apply that pertain to water quality, water discharge, wetlands, air emissions and mine safety. Environmental review in the form of an Environmental Assessment Worksheet (EAW) is required for operations that will exceed 40 acres to a mean depth of 10 feet. Local government is responsible for the preparation of an EAW. For more information about the permits that may be required for sand and gravel mining, contact your local planning office.

Q: There's an abandoned gravel pit near my home that I think should be cleaned up. Are there state regulations and resources available for gravel pit reclamation?

A: There are no statewide requirements or funds for the reclamation of gravel pits in Minnesota. Sand and gravel operations, including reclamation, are most directly handled at the local government (township, city, and/or county) level. Plans for the reclamation of currently active gravel operations may be included as part of the mining plan developed by the pit operator, and may be required by a local government. The county planning office or landowner can tell you about plans for final reclamation.

More information about reclamation: A Review of Regulations Regarding the Reclamation of Sand and Gravel Pits in Minnesota (1989) and A Handbook for Reclaiming Sand and Gravel Pits in Minnesota (1992). You can obtain these documents from the Division of Lands and Minerals St. Paul or Hibbing offices or in some libraries.

While there are no state funds for gravel pit reclamation, 33 counties administer the Aggregate Material Tax (Minn. Stat. 298.75). In these counties, 15 percent of the tax raised from current gravel operations is set aside for the reclamation of abandoned gravel pits on public land. Several gravel pit reclamation projects on public land have been partially funded by the proceeds from this tax. The counties authorized to collect this tax in 2011 were: Becker, Benton, Big Stone, Carver, Chisago, Clay, Cottonwoods, Dakota, Freeborn, Goodhue, Hennepin, Kandiyohi, Kittson, Le Sueur, Marshall, Meeker, Mille Lacs, Norman, Pennington, Polk, Ramsey, Red Lake, Rice, Rock, St. Louis (Midway Township & Solway Townhip), Scott, Sherburne, Sibley, Stearns, Steele, Washington, Wilkin, and Wright. Contact your county planning office for more information.